FIG. 24 shows an example of a conventional joint connector block (referring to Japanese Utility Model Application Laid-Open No. H5-29230).
The joint connector block 51 includes: an upper casing 52 made of synthetic resin; lower casing 53 made of synthetic resin; and a plurality of busbars 54, each of which includes terminals and is arranged in a line in the lower casing 53. Each upward tab terminal 55 of the corresponding busbar 54 projects in a corresponding connector housing 56 of the upper casing 52, thereby enabling a connector (outside connector) of an external wiring harness to be coupled with a connector consisting of the tab terminals 55 and the connector housing 56.
A plurality of the tab terminals 55 are arranged forming a line in the longitudinal direction of the corresponding busbar 54. Each tab terminal 55 projects in the corresponding connector housing 56, thereby joint-connecting each outside connector to the connector consisting of the tab terminals 55 and the connector housing 56 through the corresponding busbar 54. Thereby, electric power circuits or ground circuits of the outside connector are electrically connected. The joint connector block 51 is mounted on a motor vehicle and so on.
However, since the busbars 54 are arranged in a line forming a plurality of lines in the conventional joint connecter block 51, the positions of tab terminals 55 for joint-connecting corresponding outside connectors and positions of female terminals for joint-connection in the corresponding outside connectors are limited, causing difficulty for meeting a demand of a complicated circuit structure and difficulty for meeting a demand of a different circuit form varying depending on types of vehicle, and causing a problem that the joint connector block 51 must be designed and manufactured per a type of vehicle every time.
For example, Japanese Patent Application Laid-Open No. H7-147718 proposes a busbar structure (not shown in a figure) of an electric junction box, in which connectors are joint-connected with each other by arranging busbars in two directions, i.e. in the longitudinal and lateral directions. However, in this structure, when an outside connector is to be joint-connected, similarly to Japanese Utility Model Application Laid-Open No. H5-29230, only a tab terminal of a busbar extending in one direction is used to joint-connect the connector to the outside connector, causing difficulty for meeting a demand of a complicated and highly dense circuit form and difficulty for meeting a demand of a different circuit form which varies depending on types of vehicle.